<template>
  <div>
    <router-link tag="div" to="/" v-show="showabs">
      <div class="header-abs">
        <span class="iconfont header-abs-back">&#xe624;</span>
      </div>
    </router-link>
    <div
      class="header-fixed"
      v-show="!showabs"
      :style="opacityStyle"
    >
      <router-link tag="div" to="/"><span class="iconfont header-fixed-back">&#xe624;</span></router-link>
      景点详情
    </div>
  </div>
</template>
<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showabs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handlerScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showabs = false
      } else {
        this.showabs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handlerScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handlerScroll)
  }
}
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl'
  .header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    background-color rgba(0,0,0,.8)
    display flex
    justify-content center
    align-items center
    .header-abs-back
      color #fff
      font-weight bold
  .header-fixed
    z-index 3
    position fixed
    top 0
    left 0
    width 100%
    background $bgColor
    height $headerHeight
    line-height $headerHeight
    text-align center
    color #fff
    font-size .32rem
    .header-fixed-back
      position absolute
      left 0
      top 0
      width .64rem
      color #fff
      font-size .4rem
</style>
